In her blog post, Ms Wilson said she had unsuccessfully tried to sell the company, but had struggled to find a buyer given her name was so central to the brand.

As a result, she has decided to shut it down altogether.

“Success is a funny thing. It requires feeding. It requires growth. Which sees you become caught up in the cycle eventually, sometimes without realising,” she wrote.

“Once we arrived at the point where ‘scale’ — growing the existing structure exponentially — was required, I realised the motivator now was money.

Sarah Wilson’s book was a bestseller.Source:Supplied

“My motivator had not been money previously, a freedom that enabled me to make bold decisions that at times startled peers and the industry, but ultimately, and ironically, saw my message and product spread further.

“So I decided a little over 12 months ago that it was time for me to go. I’m an educator, a communicator. Not a money-spinner. It was best for everyone and for the message.”

Ms Wilson denied the decision had been made because her business was failing or that she was “mentally unfit” for the challenge.

The company will not close immediately, and followers will still be able to participate in the I Quit Sugar program until early April.

According to the company’s figures, more than 1.5 million people have quit sugar through the program since it was launched.

But despite the company’s success, Ms Wilson said keeping it operational would be hypocritical.

“Hypocrisy seeps in if I remain someone who sacrifices my own wellbeing and values for money and success,” she said.

Ms Wilson said she had “a lot more to create and a lot more education campaigns to ignite”, and that she was particularly focused on tackling anxiety and food waste in future.